The “INESA Lighting Handbook” published by the Illuminating Engineering Society of North America, is incorporated by reference here in its entirety. As discussed in chapter seven of that handbook, a “luminaire” is a device for producing, controlling, and distributing light. It is typically a complete lighting unit consisting of one or more lamps, sockets for positioning and protecting the lamps and for connecting the lamps to a supply of electric power, optical devices for distributing the light, and mechanical components for supporting or attaching the luminaire. Luminaires are also sometimes referred to as “light fixtures.”
So-called “flush-mounted” or “recessed” luminaires are typically mounted behind a ceiling, wall, or other structure so that light is emitted through an opening cut through the outer surface of the structure. In order to hide the imperfect edges of that opening, “trim” can be arranged on the outer surface of the wall with a flange or “collar” that covers the edge of the opening. When plaster or other joint compound is added to make the collar flush with the outer surface, the collar is sometimes referred to as a “plaster” collar, or “flush trim” collar.
For example, U.S. Pat. No. 6,474,846 is incorporated by reference here in its entirety and discloses a flush trim collar lighting system partially reproduced in FIGS. 1-3 herein. As shown in FIG. 1, this conventional technology includes a support ring 19 having a radially planar portion 21 that is secured against the bottom of light accommodation box 13 by screws 25. Below the ceiling board 31, a finishing ring 41 has a radially extending flange 43 with apertures 45 to help hold wall joint compound. The finishing ring 41 is secured with respect to the support ring 19 by aligning cutouts 53 with inwardly protruding engagement structures (not shown) on the axial portion 23 of the support ring 19, and then turning the finishing ring.
Alternatively, as best shown in FIG. 2, screws 67 may be threaded through apertures 65, 71, or 73 in the support ring 19 so as to engage apertures 69 of the finishing ring 41. In another configuration shown in FIG. 3, threads 74 are provided on an outer surface of an axial portion 23 of the support ring 19 for engaging threads 75 on an internal surface of the finishing ring 41. The excess of the axial portion of the threads 74 extends downwardly past the finishing ring 41 to form a stop or rim, similar to rim 47 (in FIG. 1), to limit the concentric inner extent of drywall compound.
During installation, the metal accommodation box 13 is fitted with the support ring 19 and a central aperture 33 is formed in the wall or ceiling board 31 beneath where the box 13 is to be mounted. Next, the box 13 is secured, typically with respect to beams, rafters or other structural members of a building, in a position where the support ring 19 may partially fit through the central aperture 33. Next, the upper wall 51 of the finishing ring 41 is moved upwardly and into the axial portion 23 of the support ring 19 such that the inwardly protruding engagement structures fit within the radially outwardly disposed groove. A short turn of the finishing ring 41 secures it into place such that the radially extending flange 43 lies closely adjacent to the surrounding wall or ceiling board 31 and flatly against it.
Next, the joint compound is applied to the wall or ceiling board 31 around and onto the finishing ring 41 up to the rim 47. Typically smoothing will be performed by a wide blade tool. Once the joint compound dries, the whole area is sanded and the addition of joint compound possibly repeated. The surrounding surfaces, joint compound and possibly the rim 47 are then ready for painting.
U.S. Pat. Nos. 4,274,615 and 5,221,069 are also incorporated by reference here in their entirety.